1. Field of the Invention
The present invention relates to a compress and position apparatus, and more particularly, to a compress and position apparatus with positioning, orientating functions and providing more uniform pressing force.
2. Background of the Invention
In wafer bump electroplating technology, a substrate such as wafer is placed on a cathode, and metal ions from anode and plating solution are attached on the wafer to form a metal bump. A conventional electroplating method is disclosed in U.S. Pat. No. 6,156,167. A wafer is placed on a seal, and a base of a compress and position apparatus is directly pressed on the rim of the wafer so that the seal under the wafer is deformed to prevent the plating solution from polluting the region in the back of the wafer.
FIG. 1 is a schematic view of a conventional compress apparatus. Referring to FIG. 1, the conventional compress and position apparatus comprises a guiding column 102, a base 104 and a housing 106. The housing 106 is mounted on the base 104, and the guiding column is positioned in a space formed by the housing 106 and the base 104.
The guiding column 102 has a first end 112 and a corresponding second end 114. The first end 112 is fixed and the diameter of the second end 114 is greater than the diameter of the first end 112. The second end 114 has a groove 116 receiving an elastic element 118 such as an O-ring so that the second end 114 can abut the inner wall of the housing 106 by the elastic element 118 when the housing 106 moves.
In addition, the housing 106 has a central opening 120 on the top thereof and a first vent 122 and a second vent 124 on the lateral surface thereof. The central opening 120 also has a groove 126 receiving an elastic element 128 such as an O-ring. As described above, the first end 112 of the guiding column 102 is fixed. For more detail, the first end 112 passes through the central opening 120 of the housing 106 and is fixed onto other component outside. The elastic element 128 received in the opening 120 abuts the guiding column 102 when the housing 106 moves up and down.
Therefore, in the conventional compress apparatus, when gas is provided through the first vent 122, the housing 106 and the base 104 rise up. When gas is provided through the second vent 124, the housing 106 and the base 104 lower down. The base 104 moves downward to press the substrate 110 such as a wafer disposed on a cathode 130 and a seal 108 such as a sealing lip or an O-ring.
However, in such conventional compress apparatus, the base must be parallel to the seal to make the seal uniformly deformed so that an excellent sealing is available. If the base is inclined toward the seal, the seal have to compensate the incline so that non-uniform deformation of the seal will occur when the substrate is pressed by the base. Particularly in largeincline between base and seal, a portion of the seal may not function well so that the plating solution will leak to pollute the back of the wafer and the cathode. In such condition, if the pressing force is increased to avoid such bad sealing, the wafer is easily broken, particularly for a thin wafer.
Moreover, the base of prior art will rotate and is inapplicable for plating the directional wafers.